Therapeutic supports for bedridden patients have been well known for many years. Such therapeutic supports include inflatable mattresses and cushions, as well as a variety of foam mattresses and cushions. Most therapeutic mattresses and cushions are designed to reduce “interface pressures,” which are the pressures encountered between the mattress and the skin of a patient lying on the mattress. It is well known that interface pressures can significantly affect the well-being of immobile patients in that higher interface pressures can reduce local blood circulation, tending to cause bed sores and other complications. With inflatable mattresses, such interface pressures depend (in part) on the air pressure within the inflatable support cushions. Most inflatable therapeutic mattresses are designed to maintain a desired air volume within the inflated cushion or cushions to prevent bottoming. “Bottoming” refers to any state where the upper surface of any given cushion is depressed to a point that it contacts the lower surface, thereby markedly increasing the interface pressure where the two surfaces contact each other.
One type of therapeutic support is an inflatable cushion used as an overlay (i.e., a supplemental pad positioned on top of an existing structure, such as a mattress). For example, the Sof-Care® cushions made by Gaymar Industries, Inc. are cushions which overlay an existing mattress and which include a multitude of lower individual air chambers and a multitude of upper individual air chambers with air transfer channels therebetween. Air is transferred through the interconnecting channels to redistribute the patient's weight over the entire bed cushion. A three layer overlay cushion (see FIG. 3 to appreciate the three layers contact each side of the cushion) known as the Sof-Care® II cushion continually redistributes patient weight through more than 300 air-filled chambers and may include hand grips at the side of the cushion to assist in patient positioning. In these types of cushions, the individual air chambers remain pressurized.
A Sof-Care® II cushion embodiment is shown in FIGS. 1 to 3. The cushioning device 10 includes a cushioning section 12, which supports the user and provides pressure relief to the user so that the development of pressure ulcers is prevented or retarded. The cushioning section includes first and second sides 14 and 16.
As shown in FIGS. 1 and 2, the cushioning section 12 is an inflatable bladder having a first surface 20 and an opposing second surface 22 (i.e., the cushioning section 12 is capable of being filled with a fluid). The bladder is made of three layers of suitable puncture-resistant vinyl film or other suitable air impervious flexible material. However, the bladder may be made of two layers of air impervious flexible material, if desired.
The cushion also may include handle structures 18a and 18b (FIGS. 1, 2, and 3). The handle structures 18a, 18b are extensions of the first surface 20 and the opposing second surface 22 that define the first and second sides 14, 16 of the fluid cushioning section 12. The cushioning device 10 is a simple, one-piece device for home or hospital use which eliminates the need for on-site assembly, thereby making the cushioning device 10 easy to use for an untrained user.
The bladder has a plurality of button welds, illustrated at 24, to inhibit ballooning of the bladder. The button welds 24 produce, as illustrated in FIG. 3, an upper layer 26a and a lower layer 26b of a plurality of interconnected cells 26 in the cushioning section 12. Such upper and lower layer bladder systems have been previously disclosed, for example, in U.S. Pat. No. 5,794,289, which is hereby incorporated by reference in its entirety. The number of cells 26 in the cushioning section 12 may vary, however, suitable numbers of cells 26 include from about 150 to about 300 cells in an ordinary overlay cushion mattress. As the cells 26 exchange air or any other suitable medium, the user's weight is redistributed over the entire cushioning section 12. The cushioning section may have a height when inflated to a desirable level of about 3½ inches. However, the cushioning section's 12 height may be varied as desired. The cushioning device 10 includes at the foot end a connector 28 for receiving air from an inlet hose. However, the connector 28 may be placed at any position on the cushioning device 10.
The Sof-Care® II cushion (a) in a two layer embodiment, had the top polymeric material 20 sealed to the bottom polymeric material 22 at the edges 14 and 16 (see FIG. 1), and the various button welds 24 (see FIG. 5); (b) in a three-layer embodiment, had (i) the top polymeric material 20, a middle layer 21, and the bottom polymeric material 22 sealed together at the edges 14 and 16 (see FIGS. 1 and 4), (ii) the top polymeric material 20 sealed to the middle layer 21 to form top button welds 24a; and (iii) the bottom polymeric material 22 sealed to the middle layer 21 to form bottom button welds 24b (see FIG. 5).
In some embodiments, the edges 14, 16 are extended. The extended edges, as illustrated in FIG. 6 have handle apertures 18a, 18b. The handle apertures 18a, 18b are large enough to receive a conventional hand. When a person places their hands in the desired handle apertures 18a, 18b, the person is able to move the cushion.
There is a problem when a handle is used in the prior art cushion design. When the person pulls the cushion from the handle, the person also pulls on the seals at the button welds 24 and the edges 14 and 16. Pulling the seals in the prior art cushion design with a patient thereon during patient transfer processes increases the chance of leakage at the respective buttons welds 24 and edges 14, 16. Leakage at the button welds and edges is undesirable because it results in bottoming, described above, and/or immediate air losses. Immediate air losses sometimes occur when seals are damaged and the air is directed toward the edges 14, 16, not to the desired cells. Once the air is directed to the edges, the edges increase in size and form a “hot-dog roll” structure about the patient and then the edges may burst. Obviously, leaking, bottoming and immediate air losses are undesirable effects when a person re-positions a prior art cushion.
The current invention solves that problem in a unique three-tiered cushion design. The present invention is directed to overcoming these and other deficiencies in the art.